Since at least April 2009, when incumbent Pennsylvania senator Republican Arlen Specter switched to the Democratic Party, the Pennsylvania Senate race has been one to watch. At the time, however, most pundits expected the November 2 contest to be between Specter, first elected in 1980, and Republican Pat Toomey, who served in the U.S. House (1999-2005) before retiring as promised after three terms. The staunch conservative had challenged Specter in the 2004 Republican primary, losing only by 17,000 votes. Indeed, it was Toomey’s presumed strength within the Republican primary that pushed Specter to switch parties (though many pundits labeled Toomey’s chance of winning the Senate seat in the general election as a “long shot”).

For his jump, Specter received the strong backing of the party establishment, but a funny thing happened on his way to the Democratic nomination: nobody asked rank-and-file Democrats if they wanted Specter, and in May they duly nominated Joe Sestak, a former U.S. naval officer who was elected to the House of Representatives in 2006. (Sestak claimed after the primary that Bill Clinton had offered him a job if he left the race against Specter.)

In the highly Republican year of 2010, the race in this seemingly blue state has been quite competitive. A recent poll suggested that Sestak, who has consistently trailed Toomey by about 6-7% might be tightening the race and pulling even with Toomey or slightly ahead, but Nate Silver of the New York Times cautioned after the first poll against reading too much into this single poll (though he might re-evaluate with the second poll). Silver rates Toomey a 94% favorite, while the Daily Beast election oracle gives Toomey a 70% chance of defeating the Democrat.

The race between Toomey and Sestak has not been clean, and the latest round of ads has been “dirtier” than most. Toomey ran this spot, which begins with 20 seconds of positivity before hitting Sestak for voting for the “Wall Street bailout” and taking contributions from Wall Street bankers, branding him “too liberal with OUR money.”

Send in the dog to the rescue. Richard Nixon had Checkers. Joe Sestak has Belle. He replied with this ad, which might become a classic (for good or ill), invoking his dog “Belle.” Cue, five seconds of cute doggie. And, then Sestak reminds viewers that even the cutest dog has to relieve itself. He said it “made him sick to bail out the banks,” but that he had to do so to “clean up the mess left behind” by Toomey and George W. Bush. He says, Pat Toomey is attacking him for cleaning up his mess, complete with Sestak holding up a plastic bag filled with dog poo as he disposes of it.

It may be too little, too late for Sestak, but at least his ad team was creative. If he doesn’t overcome his deficit and defeat Toomey, at least he’ll know that he created an ad that is sure to live on in the annals of U.S. election campaigns.

* * *

Through election day on November 2, I’ll present some of the ads from the campaign trail to give our readers some insight into what their fellow Americans are seeing around the country. If you have a video suggestion, please message me via Twitter.